A wide variety of memory devices can be used to maintain and store data and instructions for various computers and similar systems. In particular, flash memory is a type of electronic memory media that can be rewritten and that can retain content without consumption of power. Unlike dynamic random access memory (DRAM) devices and static random memory (SRAM) devices in which a single byte can be erased, flash memory devices are typically erased and written in fixed multi-bit blocks or sectors. Flash memory technology evolved from electrically erasable and programmable read only memory (EEPROM) chip technology. Flash memory devices are less expensive and denser as compared to many other memory devices, meaning that flash memory devices can store more data per unit area.
Flash memory has become popular, at least in part, because it combines the advantages of the high density and low cost of EPROM with the electrical erasability of EEPROM. Flash memory is nonvolatile; it can be rewritten and can hold its content without power. It is used in many portable electronic products, such as cell phones, portable computers, voice recorders, thumbnail drives and the like, as well as in many larger electronic systems, such as cars, planes, industrial control systems, etc. The fact that flash memory can be rewritten as well as its retention of data without a power source, small size and light weight have all combined to make flash memory devices useful and popular means for transporting and maintaining data. As flash memory devices have continued to evolve, the density of data stored is increased. However, accuracy and reliability should be maintained.
A continuing trend in the electronics industry is to scale down electronic devices to produce, smaller, yet more powerful devices (e.g. cell phones, digital cameras, etc.) that can perform a greater number of increasingly complex functions faster and with less power. To achieve this, semiconductors and integrated circuits (e.g., memory cells, transistors, etc.) utilized in these devices are continually reduced in size. Techniques for reducing device size include packing more memory cells/transistors into a smaller area by forming their structures and component elements closer together and/or reducing component size. However, close proximity and/or size reduction of components (e.g., memory cells) can cause contamination, reducing reliability.